key·note
noun/ˈkiːnəʊt/
/ˈkiːnəʊt/
- [usually singular] the central idea of a book, a speech, etc.
（书、演说等的）要旨，主题，基调 - Choice is the keynote of the new education policy.
新教育政策的主导原则是容许选择。 - a keynote speech/speaker (= a very important one, introducing a meeting or its subject)
主题发言；主要发言人
- Choice is the keynote of the new education policy.
- (music) the note on which the key is based
主音